Ice floors, granite walls. Monsters are nearly all ice themed. Bring double cold resistance or immunity. The White Balrog is frozen beneath 1100ft of ice.
Watery rooms and corridors separated by hills and occasional rock seams. Water themed monsters. At -200 you may be watched by The Watcher in the Water. Stairs are normal but recall is prohibited.
900 feet of pain if you lack wraithform. The walls appear normal enough, but some are only illusions and provide no cover from summons. The King in Yellow hides at the end.